[crcsmnky]

What's the overlap of users who (a) have trouble with login forms and (b) leave their email open all the time (whether browser or dedicated app)? This relies on a very high level of comfort with email and context switching.

This could potentially introduce an increase in spam if users are now instructed to click on links in emails blindly as long as they match a site that they're familiar with.

Leaving one app/tab for another seems like bad UX to me. This doesn't seem any better than the OAuth dance, even if it uses a much more seemingly familiar mechanism.

[Nav_Panel]

This seems more ideal for mobile devices. Enter name -> email notification almost immediately and use that to log in. I personally think it would be easier and faster than attempting to enter a password using the on-screen keyboard.